My Mercedes engine light came on and I used my OB and it is throwing a Po300, PO171 and a PO174. What do those codes mean?

Asked by Aug 05, 2013 at 08:27 AM about the 2003 Mercedes-Benz S-Class S 500

Question type: Maintenance & Repair

Just trying to find out what the codes mean and what I can do to fix.  Basically the car runs really good.  It kinda of misses or is rough when cold but that changes when warms up.

5 Answers

223,315

P0300 is a misfire, P0171 amd P0174 are a vacuum leak. Check all your hoses for leaks. Fire up the car and open the hood, see if you can hear any leaks, move the hoses around.

3 out of 3 people think this is helpful.

Thank you very much for your help. I am always dumbfounded sometimes at the different replies people give you. I had a mobile mechanic tell me that all I need was a coil. Your answer sounds more correct. Thanks again, Mr. Cloyd

223,315

Scan for codes again after you find the vacuum leak, see if the P0300 comes back, which can be a coil.

925

Ignetion coil cause miss fire !

315

Maybe the time to change AIR FLOW MITER Sensor, Make sure its not for eBay or cheap from China. Try to get original one.

Your Answer

Add photo

Related Questions

S-Class

Looking for a Used S-Class in your area?

CarGurus has 6,396 nationwide S-Class listings starting at $2,999.

ZIP:

Search Mercedes-Benz S-Class Questions

Mercedes-Benz S-Class Experts

#1 Tom Demyan
Tom Demyan
Reputation 720
#2 Michael Kane
Michael Kane
Reputation 520
#3 lightGear
lightGear
Reputation 410
View All

Related Models For Sale

Used Mercedes-Benz E-Class
550 Great Deals out of 23,196 listings starting at $1,450
Used BMW 7 Series
168 Great Deals out of 5,947 listings starting at $3,400
Used Mercedes-Benz C-Class
847 Great Deals out of 32,130 listings starting at $1,200
Used Mercedes-Benz SL-Class
82 Great Deals out of 3,301 listings starting at $2,988
Used Audi A8
53 Great Deals out of 1,808 listings starting at $2,000
Used Mercedes-Benz CL-Class
32 Great Deals out of 631 listings starting at $3,295
Used Land Rover Range Rover
101 Great Deals out of 4,865 listings starting at $5,000
Used BMW 5 Series
592 Great Deals out of 14,886 listings starting at $1,000
Used BMW 6 Series
93 Great Deals out of 3,247 listings starting at $4,895
Used Mercedes-Benz G-Class
9 Great Deals out of 966 listings starting at $22,500

Used Cars For Sale

2017 Mercedes-Benz S-Class For Sale
1,352 listings starting at $97,675
2016 Mercedes-Benz S-Class For Sale
9 Great Deals out of 221 listings starting at $70,977
2015 Mercedes-Benz S-Class For Sale
35 Great Deals out of 589 listings starting at $44,762
2014 Mercedes-Benz S-Class For Sale
22 Great Deals out of 556 listings starting at $43,995
2013 Mercedes-Benz S-Class For Sale
22 Great Deals out of 277 listings starting at $27,995